Method and means for making automatic &#34;change over&#34; in moving picture apparatus



Sept. 1l, 1934. A. PRITCHARD 1,972,904

METHOD AND MEANS FOR MAKING AUTOMATIC "CHANGE OVER" IN MOVING PICTUREAPPARATUS Filed Oct. 28, 1932 2 Sheets-Sheet l ma. 15 bw wm www NNM. FTNNN 40m. www Y Quo, M. .NNN QWN QNN QQ N65 www Mmm, www@ mw 1,972,904"CHANGE OVER" IN MOVING PICTURE APPARATUS 2 Sheets-Sheet 2 A. PRITCHARDMETHOD AND MEANS FOR MAKING AUTOMATIC Filed 061'.. 28. 1932 IQ M SSW

Patented Sept. l1, 1934 t METHOD AND MEANS FOR MAKING AUTO- MATrc CHANGEOVER 1N MOVING Plc- Tomi APPARATUS f Alf Pritchard, Coronado, Calif.Application October 28, 1932, Serial No. 640,101

l Claims. (Cl. 88-17) This invention relates to a method and means atedierent units of a motion picture projectof making an automatic changeover in moving ing and operating mechanism. picture apparatus, andparticularly pertains to Fig. 2 iseI view in diagram showing the changemeans for automatically' starting a second proover apparatus as used inconnection with me- 5 jecting machine at the conclusion of theoperachanical means for making electrical contact in 60 tion oi theiirstprojecting machine. the circuits of projecting machine operating In theoperation of projecting machines where units. multireel films are shownit is necessary to use Fig. 3 is a view in plan showing a form of thetwo moving picture projecting machines, one of present invention inwhich color features are i0 which will be normally inoperative and mustbe embodied to be acted upon by light beams.

set in operation at approximately the same mo- Fig. e is a view in planshowing a fragmentary ment that an operating machine reaches the endlength of motion picture nlm and indicating the of the reel which it isshowing, in order that the various manners in which the lm may bepremoving picture will have continuity and so that pared for use in thevarious forms of the apparai the action will not be interrupted whenchanging tus shown in the preceding iigures. iii to consecutive reelsyci iilrn. This Operation of Referring more particularly to Fig. i of thechanging over from one projecting machine to drawings, indicates alength of motion picture the other has been in most cases brought aboutfilm having the usual picture france sections il manually and with thenecessity for the continalong one side of which is a sound track l2 'oydo ued attention of the operator. Various expediwhich sound isphotographically recorded. This 'Z5 ents have been provided in anattempt to produce sound track is usually of the form indicated at thischange over automatically, such struc- 13 or the form indicated at 14.It is, however, to tures having included mechanical metering beunderstood that these two forms of sound track means or trip mechanism,and in some instances are shown on the same lm for sake of conthe use oobstructions or contact members on. venience in illustration only. Inthe iirst men- Si) the film whereby mechanical or electrical meanstioned form of sound track the sound lines exhavebeen set in operation.Heretofore most of tend entirely across the track and vary in densitythese devices have proven unsatisfactory due to and Width, while in theform of sound track indithe fact that they require the use ofobjectioncated at le the sound track is rendered Opaque able additionalequipment and for the further along one of its sides, the opposite sidehaving a 85 reason that they have not been accurate in their serratededge. At 15 in Fig. 4 an area is indicated performance. It is theprincipal object of the on the opposite side oi the lm from the soundpresent invention therefore to provide means for track which is of aselected color and for a pur- 'automatically producing a change overfrom pose to be hereinafter set forth. The color area 3o one projectingmachine to another in a positive may be used o n a lm with certainapparatus, or 90 and precise manner without theuse of lmechanithe areas13' or 14 may be used. It will be uncal equipment and the attendant careand adderstood that when any one of these areas is used justment whichmust be given this equipment in on the edge oi the film opposite thesound track an attemptto cause it to function properly. 12 the otherareas are not used.- This opposite 40 The present invention contemplatesthe proedge of the iilm from the sound track will here- 95 vision ofmeans embodied in a moving picture inafter be designated as thefrequency strip 16, projecting machine, and which means is dependand itis with this particular area of the iilm that ent upon a'beam of lightpassing through a movthe present invention is concerned in a manner ingpicture iilm and being acted upon by the lm to control the presentdevice.

in a manner to initiate an automatic change Referring more particularlyto the left side of 100 over without requiring the presence of any me-Fig. 1 of the drawings, 17L indicates the usual chanical trip meansacted upon by the film or exciting lamp for a slit lens ISL,v (In-viewof the carried thereby. fact that the invention is shown in diagram inThe invention is illustrated by way of example Figs. 1 and 2, and forthe further reason that 5o in the accompanying drawings in which: mostof the parts are in duplicate, thesame ref- 105 Figure 1 is a view indiagram indicating in a erence numerals will be used throughout withgeneral manner the application of the present identical or duplicateparts, but with the addiinvention toa moving picture projecting machinetional use of the letters R and L to indicate parts in which soundiilmis projected and which inof right and left hand machines). 'Ihislens '5 volves the use of a series 'of relay circuits to actuprojects abeam of light through the sound track 11o area 16 of the lm 20 asdirected through an aperture 19L in an aperture plate 19L. The beam oflight from the slit lens 18L then passes to a photo electric cell 22L.

It is contemplated in the present invention to utilize the beam of lightfrom the exciting lamp 17L to initiate and control the operation of asecond 4projecting machine through variation in the light value of thebeam caused by the fact that the beam will encounter a frequency area13' or 14 along the frequency strip 16 of the film and that thisfrequency area will be so positioned with relation to the length of thestrip as to initiate the operation and control circuitsv for a secondprojecting machine, or other circuits to be controlled and by whichvarious pieces of apparatus might be operated, as will be hereinafterdescribed. It may be desirable to apply a color area to the frequencystrip as indicated at l5 as a substitute for the frequency areas 13 or14', and by which the same results of change overi are obtained, as willbe hereinafter explained. An apparatus for this purpose is shown in'Fig.3 of the drawingsand will be hereinafter described.

The beam of light from the exciting lamp 17L and the slit lens 18L willpass through the aperture 19L to the photoelectric cell 22L. This cell-Will be impressed with a light impulse of the frequency represented bythe frequency strip 13' or 14', as recorded on the prepared film.Connected with the photoelectric cell are conductors 29L and BOLcarrying current impulses finally to a. resonant circuit which islresonant at the frequency recorded on the film. vThis circuit derivesits power from a source of low voltage supply indicated at 31L and whichis connected to wires 34L and 35L respectively. A conductor 38L leads tothe positive side of filament 39L of a vacuum tube generally indicatedat 40L. 'I'he negative wire from this iilament as indicated at-41Lconnects with the Wires 30L from the photoelectric cell 22L. The wire.291.. which leads from the other pole of the photoelectric cell connectswith a condenser 42L and the condenser in turn is connected by aconductor 43L with the grid 441, of the vacuum tube 40L. A resistance45L is connected across the line from the conductor 301'.' to conductor43L. The conductor 30L also connects with wire 41L and a return leadwire 46L which connects with conductor 35L. A second source ofelectrical energy is indicated at 48L. The negative pole of this sourceof energy connects with conductor 35L. 'Ihe positive pole of this sourceof energy connects with conductor 49L which is secured to a conductor52L connected with the resistance 54L which is attached to the wire 29Lupon the opposite side of the condenser 42L from the point of attachmentof the resistance 45L. Theconductor 52Lalso connects with the primarywinding 55L of a transformer 56L. The opposite side of this winding isconnected to the plate 57L of the vacuum tube 40L by means of aconductor 581.-'. A secondary winding 59L of the transformer connectswith conductors SGL and 61L which lead to the winding of a. magnet 62L.In the drawings similar conductors lead to magnets 63L, 64L, and 65Lwhich close switch members 66L, 67L, 68L, and 69L, respectively, for apurpose and in the manner to be hereinafter set forth. The circuits ofmagnets62L, 63L, 64L, and 65L are provided with series resonancearrangements including an inductance coil 70L and the condensor 71L inseries with the magnet winding. The capacity of the condenser in eachinstance and the electrical valuesof a condenser 71L and an inductancecoil -70Ii plus the inductance of the magnet are such as to neutralizeeach other when excited by a current of certain or desired frequency. Itis of course well known that with a given adjustment of capacity andinductance or a given relation between them. their reactance willbalance out for one certain frequency, and current at this frequencywill then iiow through the circuit in maximum volume although currentsat any other frequency still will be opposed by the reactances. In thiscase the established different capacitance and inductance values of theseveral magnet circuits will cause these circuits to become resonant atdiierent frequencies as separately controlled by the current iiowingthrough the circuit caused by the variation of light impulses impressedupon the photoelectric cell.

In the form of the invention shown in Fig. 1 of the drawings, it isintended that when a desired frequency is impressed upon the resonantcircuit it will lselectively actuate the correspondingly relay magnets62L, 63L, 64L, and 65L. It will therefore be evident from the foregoingthat by varying the values of the inductance and the capacitance in theresonant circuits of the separate'relay magnets, it is possible to causethe magnets to operate at diierent intervals and at diierent points ofvtime with relation to each operation. As here shown, the relay magnet62L is intended to close a circuit to a bell or other signal 73 havingasource of electric energy 25. The relay 65L controls the projector motorcircuit as will be hereinafter described and relay 63L controls thepicture change over apparatus while relay 64L controls the sound changeover apparatus. 'I'he switch blade 66L of the relay 62L establishescommunication between conductors 74L and 75L and the source of supply25, thus establishing electrical connection with the bell 73. The switchblade 69L closes the circuit from a source of electric supply, throughlead wires 36 and 37 and through the conductor 76L to one side of themagnet 78L of an interlocking relay switch which simultaneously operatesa contact member 79L establishing a circuit through conductor 80L toconductor 81L and thence through switch 82L by which the projectionmachine motor 32R may be normally stopped if desired. The

circuit then continues through conductor 831. to

a switch 84L by which the projection machine may be normally started ifdesired. This circuit is then completed to the return lead wire 85L tothe feed wire 36. The contact'member 79L of the relay 78L also completesthe circuit through the motor 32R of a moving picture projectionmachine. This motor receives its current supply from main lead wires 87and 88 which may be controlled by a make and break switch 89B,interposed in the line 88R and through which the circuit may pass tomotor 321iI and thence along wire 90R to the contact member 79L, fromwhich the circuit continues along conductor 91 to feed line 87. Therelay 65L when engaged closes a circuit from feed wire 36 through wire85L to the switch blade 69L and then through conductor 50L to magnet 78Lafter which the circuit continues along conductor '76L to feed wire 37.

The relay 64L will act to close its switch 68L to establish a circuitfrom conductors 91R and 92B. which is connected in the sound system. Asecondary winding in the relay coil is energized by an interlockingcircuit and maintains the circuit through conductors 91L and 92L` closedafter the relay 64Ll has vbeen initially energized and until tinuesthrough wire 94L to the switch blade 68L and then along conductor 95L tomanually operated switch 96. A wire 95B then contacts with switch blade67B of relay 63B. Due tothe arrangement here shown the relays 63R servesthe dual purposes performed on the other side by relay 63L and 64L.'This circuit is then completed through conductor 93R to feed wire 37.

In tracing the circuits through the sound equipment it will beunderstood that the major circuits are shown only and not the manysecondary or power input circuits with which said apparatus 'may beconcerned.

In another form of the invention diagrammatically indicated in Fig. 2 ofthe drawings, single 'relays 62L or 62R are provided and variouscircuits are made mechanically by drums 124L and 124R which are drivenby motors 125L and 125R and carry a plurality of contacts. In thisdescription the left hand machine will be described with theunderstanding that the parts are duplicated in the right hand machine.

When the magnet 64L is initially energized with an appropriate resonantcurrent switch blade 68L will be drawn to make contact betweenconductors 91R and 92R, and will at the same time break a circuitthrough conductor 91L and 92L. The circuit through conductors 91L and92L includes left projecting machine to the main amplifier 97 whichamplifier is common to both machines. This circuit is as follows: Fromamplifier SSL. of the left hand projecting machine thesound currentspass through switch blade 68L to conductor 91L and thence alongconductor 99 to a fader 100. The other side of the fader connects withamplifier 98L by a wire 101L and 102. The sound apparatus initiating andcontrolling the production of sound currents for both projectingmachines are indicated in diagram only and since their details are of noconcern here the parts will not be given reference numerals. A wire 102completes the circuit through the fader from the conductor 101L. Wire103 and 104 connect the fader with the amplifier 97. Wire 105 and 106connect the amplifier 97 with a loudspeaking telephone 107. When theswitch blade 68L moves to contact with conductors 91R and 92R a soundcircuit is completed to the main amplifier 97 from the amplifier 98B. ofthe right hand projecting machine and the sound circuit for the lefthand machine is broken. The relays 63L and 63R alternately controldowser blades 108L and 108B. The control circuit for the left handdowser is as follows: Current ows from lead wire 37 to wires 109R and109L. The circuit continues through switch blade 67L to conductor 110Lwhich connects with the winding of a relay 111L by which a switch blade112L is drawn into engagement with conductors 113L and 114L when therelay 111L is energized. The conductor 114L leads to one side of asource of electric energy 115. The other side of this source of energyis provided with a conductor 116. This wire connects with wires 117L and117R. 117L leads to one winding of the solenoid 118L. The circuit thencontinues along wire 119L to wire 113L. The conductor 116 also leads towire 120L and 120B. Wire 120L leads to another winding on solenoid 118L'after which the circuit continues along Wre 121L to wire 122 whichconnects with wire 113R. The dowser discs act in conjunction with thelamp houses 12,3L and 123B.

In operation of the form of the invention shown in Fig. 1 of thedrawings it will be understood that the film which is being used in dualmotion picture projection machines has been specially prepared inaccordance with one of the methods indicated in Fig. 4 as represented bythe frequency -Iields 1314. 'Ihese elds will occur near the source 17Lor 17R to set up a state of resonance inthe circuits of relays 62, 63,64 and 65, either right or left, in which the resonance frequency of thecircuits will correspond to the light variation frequency of the beam oflight as controlled by the eld 13 or 14 onthe lm. It will, of course, beunderstood that the resonance frequency of the several relay circuitsmay be selectively determined and may be varied with relation to eachother in a manner to insure that the various relays may operatesimultaneously or in any desired sequence. In a preferred manner ofoperation the relay 62L is actuated rst and this in turn produces awarning signal such as ringing bell 73. The relay 65L is then energizedto start the motor of the right hand projecting machine. When thisoperation is initiated the motor of the left hand machine is stillrunning, and consequently the film in the left hand machine is stillshowing. Likewise the dowser plate 108R of the right hand machine is ina shielding position over its lamp house. A resonant circuit is then setup for dowser relay 63L which causes one winding of the solenoid 118L toswing dowser plate 108L to an obstructing position and one winding of1l8R to swing dowser plate 1081il to a non-obstructing position.Simultaneously with this action relay 64L is energized with a suitableresonant frequency current to break the sound circuit to the left handprojecting machine and establishing the circuit to the right handprojecting machine This magnet 64L also establishes an interlockingcircuit through wire 93L and 95L through switch blade 67B.- of relay63B.. The complete change over has thus been made.

In a reverse change from the right hand machine to the left handmachine, the operation is identical except that the relay 63R serves thedual purposes of relays GBL and 64L and restores the original soundcurrent through the left hand machine while breaking the sound circuitof the right hand machines. In Fig. 2 the interlocking relay .126L isenergized'from an electrical source, such as indicated at 127L. A wire128L leads from the source to switch blade 129L after which the currentpasses through magnet 126L along wire 130L. The current is thencompleted to the source 127L along wire 131L. This will cause theinterlocking relay 126L to be energized and act upon switch blade 1321..The blade 132L closes a circuit from the electric source 127L along wire133L which connects with wire 1301. and then through wire 134L to anormally closed switch 1351.1.` The switch connects with wirej'lBGLleading to a contact brush whichwill engage a commutator segment 137L ondrum 124L.

The drum 124L isdriven by the motor 125L through gears 138L and 139L.The motor circuit is controlled by the interlocking relay 126L sub--source and. a `wire- 141L^leading to. motor 125L. A return-lead Wire142L connects the source of current with .the motor. 125L through switch1:4=3L.'-f.A tell-tale light .may be connected across tliemotor circuit.The drum segment 137L completes a circuit from wire 136L to wire 144LWhich-connects with a feed wire L ofr the electric source 12'7L. Thiscircuit sustains the interlocking relay 126L afterstherelay 62L hasbecome deenergized. The circumferential length of--drlnn-fsegment 137LisA such asto maintain this circuit until the routinev of all oftheother contact.. circuits' have functioned, and the drumhas'substantially.completed. a revolution of its operation.v

^ It is to-be understoodv that the functions of right and left :handrelays 62, 63, 64 and 65, shownin Fig. 1 are performed in the structurerof Fig. -2 by right'and left hand drum segments 146, 147, 14S-and 149.In the structure of Fig. 1- the sequence of power of the relays wascontrolledA by the creation of suitable resonant circuits determined bythe arrangement of light frequency fields along the edge of the llm. Inthe structure of Fig.l 2, however, .the arrangement of the variouselectrical contact and conductor segments around the circumference ofthe drums will have this same eifect and control., In the two forms ofthe invention as shown in` Figs. .1 and 2 the signal circuit, the dowsercircuitsy and the motor circuits are identical so that vthe samereference characters lare universally usedl in those circuits on bothguresof the drawings.

'The soundvcircuits which have been described in Fig; 1 as beingcontrolled by relays 64L and 64H are controlled in Fig. 2 by the contactsegmentszlllL and 148B. in a slightly diiierent manner as will now bedescribed. The circuit obtains its electrical supply from source 127Lafter which the current travels along wire 149L and 1501.. to makecontact with segment 148L on the drum 1241... The circuit is thencompleted along wire 151L to wire 154L which connects with wire 145L ofthe source 127L. This circuit energizes magnet 152L and simultaneouslyinterrupts a sound relay circuit of the left hand machine and completesa sound relay circuit of the right hand machine. The left hand soundrelay circuits include magnet 155L, and the opposite circuit includesmagnet 155R. The circuit through vmagnet 155L leads from electricalsource 156 through wire 157L. A normally closed switch 158 interruptsthis circuit if desired. The wire 157L leads to magnet 155L. The otherside of the magnet carries a wire 159L which may contact with switchblade 160L of relay 152L. The relays 1521il and 152L momentarilyoperate. This momentary action of relay 152L establishes a circuit towire 161L connected with wire 162 L which leads to switch blade 160B. ofrelay 152B..

Contact is here made with wire 162B from which the circuit to the source156 is completed along wire 163.

Prior to the energization of magnet 152L the switch blade 160Lestablishes electrical contact from wire 162R to wire l164R, connectedwith wire 165R leading to a position where it may contact withinterlocking switch blade 166. A wire 167Bl connects with magnet 155B.and thence along wir-e 157B and wire 157 to the source 156i. Whenhowever, the circuit is established through magnet 152L the circuitthrough magnet energized. This is brought about through conisestablished. This willswing switch blade 166 toward magnet V155L andcomplete two circuits.

One circuit includes-wire 162L which contactsl with switch blade v166and continues along wires 167L and 159L to magnet 155L. The other cir'-cuit includes wire 91R connecting with switch blade 166 and continuingalong wire 92B to the wire 99 connected with the fader 100. Thisoperation completes the sound circuit and also the interlocking relay`circuit therefor.

Various switches are shown-in the drawings and while they may not benecessary in anapparatus embodying the invention, their presenceprovides all the necessary'controls for an operative pair of projectingmachines. A normally opened switch 168L may be usedto Aoptionally startmotor 125L. A normally openedl switch 169L controls the sound relaymechanism independently of the drum. A switch 170L is nor.

mallyr closed and maybe .used when the last reel is being run and it is.not desired to make a change over to the other machine but when it isdesirable to control the other'circuits, this switch may be opened. v .i

The switch 1'71L is normally opened and is used to manually control :theprojector motor.

The switch 1'72L is normallyclosed and is used to break the interlockingcircuit to relay 'ISL after the film being. projected. has completelyrun through the-machine.

ReferringA more particularly to Fig. 3 ofthe drawings, a device isshownwhich will eiect' a beam of light passing from a source and through thelm and light filters to pnotoelectric cells by which a circuit iscontrolled. The beam of light Will be effected by a color area, such asthat indicated at 15 ofjEig. 4,-and which is usedinstead of frequencystrips 13' and 14'. Relay magnet 62 is connected to a feed wire 19'7R bya wire 195R.

The circuit then continues along conductor 194R y to a normally openswitch blade 187B. -The circuit then continues a'ong conductor 192R to anormally closed switch blade 186R and then along wire 193B*J to a feedwire 196B.

Relay magnet 190B. is connected to a source of electric energy 181R by awire 188B. The circuit then continues along wire 185B to a photoelectriccell 179B.. The opposite side of this photoelectric cell is connected tothe source of electric energy'181R by a wire 183B..

Relay magnet 191R is connected to a` source of eectric energy 180R by awire 189R. The circuit then continues along wire 184B. toa'photoelectric cell 178B, the opposite side of the lcell is connectedto the source of electric energy 180B by a wire 182B..

In the form of the invention shown in Fig. 3

of the drawings the operation is predicated upon is passed by lightfilter 177B.. Light filter 177R is such that it wil absorb a color whichis passed by light filter 176B. When a white light is shown through thefilm, as normally would be the case, both filters will pass light whichwill fall upon their respective photoelectriccells. Thus causing bothphotoelectric cells to pass current to energize relay magnets 190R and191R. Relay magnet 190R upon becoming energized draws switch blade 187Rover to close the circuit with wire 194B., simultaneously, relay 191B.upon becoming energized draws switch blade 186B over to open the circuitfrom wire 193B. When the portion of the film upon which the beam oflight is projected'is opaque, neither cell will receive light, thereforewill not pass current to energize relay magnets 190B. and 191B., therebycausing the circuit to relay magnet 62 to be broken by switchblade-187B. When however a coloredl light, of a color which will becaused by the streak of color dye 15 on the frequency strip 16 fallsupon the color filters, filter 17'7R only will'pass this light therebycausing a current to fiow through the photoelectrie cell 179R whichcauses relay magnet 190B to become energized causing switch blade 187Rto be pulled over thereby closing the circuit from switch blade 187Bl towire 194R. completing the circuit from feed wire 196R.' to the magnet ofrelay 62.

It will be understood that relay 62, switch blade 129 and wires 128 and130 correspond to relay 62B, switch blade 129R and wires 128B and 130R.And that when the apparatus as shown in Fig. 3 is used to control relay62 the apparatus used to control relay 62R in Fig. i is not used.

It will thus be seen that the arrangement here disclosed makes itpossible for two pieces of apparatus, such for example. as two motionpicture projecting machines, to be automatically operated in sequence ascontrolled by means upon the film for varying the light value orcolorvalue of a light beam passing through the film, and being projectedthrough an area of a predetermined frequence of color.

While I have shown the preferred form of my invention as now known tome, it will be understood that various changes may be made in thecombination, construction, and arrangement of parts by those skilled inthe art without departing from the spirit of the invention as claimed.i

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In combination with a pair of motion picture projecting machines,electric circuits including driving means for said machines, means forestablishing said circuit, films adapted to pass through said machines,an exciting lamp for one of the machines by which a beam of light may beprojected through the film, an area on said lm adapted to vary the valueof said beam of light when it is projected therethrough, and. meanssensitive to said variations whereby the electric operating circuit ofthe other motion picture machine may be established when the.

beam of light projects through the aforesaid area on the film, saidlight/beam having a light variation frequency equal to the resonancefre- -quency of a circuit to be established.

2. In an apparatus of the class described, the

` combination of a pair of motion picture projecting machines adapted tobe operated in sequence,

electric operating circuits for each of said machines, a motion picturelm adapted to be run through the first of said machines, an areadisposed upon said fllm adjacent the concluding end of its run and bywhich the light value will be' varied in a predetermined manner as abeam of light is projected therethrough, an exciting lamp adapted toproject abeam of light through said film and the area thereon, aresonant circuit including a photoelectric cell and upon which cell saidbeam of Ilight strikes the resonance frequency of said circuit beingequal to the light variation frequency of the beam of light, and meanscontrolling the operating circuits of said second motion picture machineand set in motion by the establishment of the aforesaid resonant circuitwhen the beam of light has a frequency equal to the resonance frequencyof said resonant circuit whereby to control the operative circuits ofthe projecting machines.

3. An apparatus of the class described, comprising a motion pictureprojecting machine, mechanical means for closing an electric circuit, amotor for driving said ,mechanical means, a circuit controlling saidmotor, a relay switch for establishing said circuit, a resonant circuitincluding said relay switch and means whereby a predetermined change inthe value of a light beam passing through the film of the projectingmachine to agree in light variation frequency with the resonancefrequency of said resonant circuit will produce a circuit to energizesaid relay and close the circuit of said mechanical means.

4. An apparatus of the class described, comprising a motion pictureprojecting machine, mechanical means for closing an electric circuit, amotor for driving said mechanical means, a circuit controlling saidmotor, a relay switch for establishing said circuit, a resonant circuitincluding said relay switch and means whereby a predetermined change inthe value of a light beam passing through the film of the projectingmachine to agree in light variation` frequency with the resonancefrequency of said resonant circuit will produce a circuit to energizesaid relay and close the circuit of said mechanical means, a pluralityof separate operating circuits and means whereby said mechanical meanswill close said plurality of circuits in succession and in synchronismone with the other.

. 1 5. In a motion picture projecting apparatus, an

exciting lamp, -a lens forvprojecting it through a motion picture film,means on said film for changing the light value of the beam of lightpassing through the film to a predetermined light variation frequency, aphotoelectric cell upon which said light beam falls, a resonant electriccircuit including said photoelectric cell and whereby the circuit willbe established when the light variation frequency of the beam of lightequals the resonance frequency of the resonant circuit and said beam oflight falls upon the photoelectric cell, and a relay switch in saidcircuit adapted to beclosed when the aforesaid resonant circuit isestablished.

iii

LCL@

6. In a motion picture projecting apparatus, 180

an exciting lamp, a lens for projecting it through a motion picturefilm, means on said film for changing the light value 0f the beam oflight passing through the film to a predetermined light variationfrequency, a photoelectric cell- .upon which said light beam falls, aresonant electric circuit including said photoelectric cell and wherebythe circuit will be established when the light variation frequency ofthe beam of light equals the resonance frequency of the resonant passingthrough the film-to a predetermined light @variation frequency, aphotoelectric cell upon which said light beam falls, a resonant electricrcircuit including said photoelectric cell and whereby the circuit willbe established when the light variation frequency of the beam of lightequals the resonance frequency of the resonant circuit and said beam oflight falls upon the photoelectric cell, and a relay switch in saidcircuit A l`adapted to be closed when the aforesaid resonant circuit isestablished, the means upon the iilm'being a color area by which apredetermined light value may be obtained.

8. An apparatus of the class described comprising an exciting lamp, aslit lens through which a beam from said lamp vis projected, a motionpicture i'llm adapted to move along the path of travel traversing saidbeam, a color area on said motion picture lrn and by which the lightvariation frequency of said beam ispredeterminately changed in aphotoelectric cell sensitive to said light beam, a color lter interposedbetween said photoelectric `dell and the beam of light whereby all othercolor values than that of the area upon the film will be ltered out, aresonant electric circuit including said photol electric cell and arelay switch said circuit having a resonance frequency equal to thelight variation frequency of the beam of light passing through the coloreld, whereby the resonant circuit will be established when a beam oflight of a predetermined color is impressed upon the photoelectric cell.

9. A method of controlling a resonant circuit which consists in passinga light beam through a moving lm on which illm a eld occurs throughwhich said beam of light passes and by which its light variationfrequency is established at predetermined value, then causing said beamof light to fall upon a photoelectric cell included within a resonantcircuit, which circuit has a resonance frequency equal to the lightvariation frequency passing through the eld on "the lm whereby a desiredoperation will be set up by the

